Recordings

Literature

Behaviour

Vibratory Signals Courtship signals in T. neglectus were produced in sequences of pulses, emitted with a relatively regular repetition time (Figure 3, left). The mean pulse repetition time varied significantly between individuals from 1.728 s (SD 0.253 s) to 2.673 s (SD 0.533 s; ANOVA, P,0.001; n12n14 = 9275). Exclusion of the one atypical example resulted in a significant positive regression of the pulse repetition time with respect to the SP mass (Figure 4; test values in the figure legend). The mean pulse duration also varied significantly between individuals, from 0.546 s (SD 0.253 s) to 0.834 s (SD 0.122s; ANOVA, P,0.001; n12n14 = 12283). Pulses were amplitude-modulated, typically containing two or three amplitude peaks (Figure 3, left; Figure 5A, right). The mean value of the peak velocity of pulses was 0.184 mm/s (SD 0.149 mm/s) on bark and 0.063 mm/s (SD 0.046 mm/s) on moss. On moss, the mean velocity value was 9.3 dB (dB = 206log v1/v2) below the value measured on bark. We recorded no courtship signals above the noise level from the stone. Post-copulation signalling of both species induced mostly simple, non-amplitude modulated pulses in the substrate (Figure 3, right), while on some locations pulses contained two main amplitude peaks (Figure 5B, right). The mean pulse duration on bark varied between individuals from 0.590 s (SD 0.098 s) to 1.024 s (SD 0.276; n12n11 = 7257) in T. neglectus and between 0.560 s (SD 198 s) and 1.105 s (SD 0.184 s; n12n8 = 4234) in T. cavicola, with no significant differences among the species (Figure 2B; test values in the figure legend). The mean value of the peak velocity of pulses was on bark 3.556 mm/s (SD 1.621 mm/s) in T. neglectus and, similarly, 2.161 mm/s (SD 1.78 mm/s) in T. cavicola. In T. neglectus the mean velocity of the post-copulation signals was 25.7 dB above the velocity of courtship signals on bark. On the stone the mean pulse duration, as recorded for T. neglectus, was 0.256 s (SD 0.024 s; n = 10) and the mean value of the peak velocity was 0.135 mm/s (SD 0.04 mm/s). The mean signal velocity on the stone was 28.4 dB below the value on bark. Signals’ spectral properties were substrate-dependent. On the same substrate the frequency spectra were similar in both species for both signal types (Figure 5; Table 1). The spectrum was extremely narrowly banded on elm bark, with most of the energy content in the range below 150 Hz. On spruce bark and, similarly, on the stone, most spectral energy was emitted below 250-300 Hz, while on moss the frequency spectrum extended up to 600 Hz, with prominent peaks expressed in the range up to 400 Hz. The dominant frequency was expressed below 120 Hz on all substrate types.

Source: Stritih, Nataša; Čokl, Andrej (2012). Mating Behaviour and Vibratory Signalling in Non-Hearing Cave Crickets Reflect Primitive Communication of Ensifera.